Stop watch



(No Model.) 2 Sheets-Sheet 1.

' A. LE COULTRE.

STOP WATCH.

No. 284,444. Patented Sept. 4. 1883* WITNESS 4 INVBNTOR ATTORNEYS. e

N. mama PMo-Uihogm. Wilhiuflom D. c.

(No Model.) 2 Sheets-Sheet 2.

A. LE GOULTRE.

STOP WATCH.

No. 284,444. Patented Sept. 4, 1883.

Fi i

WITNESSES: INVENTOR:

ATTORNEYS.

UNITED STATES PATENT OFFICE.

AMI LE COULTRE, OF GENEVA, S\VITZERLAND.

STO P-WATC H.

SPECIFICATION forming part of Letters Patent No. 284,444, datedSeptember 4, 1883. Application filed January 24, 1883. (N0 model.)

To all whom it may concern.-

Be it known that I, Am Ln CoULTRE, of Geneva, Switzerland, have inventeda new and Improved Stop-WVatch, of which the following is a full, clear,and exact description.

My improvements relate to split secondwheels for chronograph-Watches.

The invention consists in a flexible connection uniting the spring tothe hammer or piece acting on the cam which operates the flyback, theobject being to avoid the friction, which is apt to cause the-stoppageof the split and sometimes of the watch, and also lessen the pressurewhich causes resistance to the working of the chronograph, therebyrendering the wheel reliable in operation.

In watches of this character the fly-back mechanism consists in aspecial hand joined to that, of the chronograph, so that it can fly backto allow the noting of several successive observations and theirduration. The flywheel carries a heart-cam held by friction, so as tofollow the chronograph-wheel in moving, stopping, and returning. It isat the moment when the fly-back is stopped that the delicate function isexecuted-namely, the heart continues to revolve and the hammer commencesto rise by the action of the cam. The more the hammer rises on the camthe greater and more irregular is the force of the spring acting on thehammer, and as soon as the point of the cam is passed the reverse actionoccurs and the movement is accelerated. This irregularity of friction ofthese delicate parts causes errors in the movement of the watch, andoften stops the fly-back. This fault has been corrected to some extentby bending the spring in such a manner as to decrease the leverage asthe hammer rises; but in order to obtain perfect operation, it isnecessary that the full power of the spring be exerted when the hammeris down, in order to hold the hand at its fixed point, and this pressureshould decrease as the hammer rises, so as to amount to almost nothingat the top. hen that is accomplished the fly-back, instead of being adetriment, adds to the value of the watch.

Vith this statement of the difficulties which my invention is intendedto overcome, I will now proceed to describe the construction andoperation.

Reference is to be had to the accompanying drawings, forming part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the figures.

Figure 1 is a plan view of the fly-back mechanism in one position. Fig.2 is asimilar view of the parts in reverse position. Fig. 3 is a planview of the split-second mechanism of a watch having my improvementapplied thereto; and Fig. 4 is a central vertical section of the watch,the watch-case being shown in dotted lines.

Referring to Figs. 3 and 4, A is the flyback or brake wheel, mountedloosely on the central arbor, I), stepped in the bridge 0 at the back ofwatch. d is one second-hand, secured 011 arbor Z), and c is the othersecond hand, upon sleeve 6 on arbor I), which sleeve is connected to andcarried by the wheel A. B is the heart-cam, held by friction on thearbor I), so as to turn with it, and D is a hammer, which is pressed onthe heart-cam by the spring 0. f is a ratchet-wheel, fitted for movementby the lever g and pawl 71, andi is an arm, pivoted between thespring-pressed arms j, withits end contiguous to the ratchet-wheel f, sothat the teeth of the ratchet-wheel can act on said end to turn the armupon its pivot to spread the spring-pressed armsj, to release the fly orbrake wheel when desired. It is a pawl to prevent backward movement ofthe ratchet wheel, and Z is a stem projecting through the watch-ease andconnected to lever for operating it. If it be desired to stop the hand0, the stem Z is pushed inward, when the ratchet-wheel f will be turnedand its tooth disengaged from the projecting end of the arm 27, and thespring-arms j will clamp and hold the fly or brake wheel A, and sincethe hand a is secured to the sleeve 0, carried by the said wheel A. itwill also be stopped, the hand (I, with its heart-cam l3, continuing tomove, and hammer D rolling on the edge of said cam out of its normalposition. By pressing again on the stem Z, the ratchetwheel will beturned and one tooth caused to engage the end of the arm 1 and turn iton its pivot tospread thearms j,-and thereby release the wheel A, whenthe heart-cam B, acting upon the spring-pressed hammer D, turns thewheel A, and consequently the hand 6-, for ward to hand 11.

Instead of having the spring 0 connected directly to the hammer D, Iplace between the end of the spring and the hammer a flexibleconnection, E, the same being preferably a short link pivoted at one endto the hammer, and at the other end to the spring, as shown on anenlarged scalev in Figs. 1 and 2. This piece may be of any form, so thatit has the same function. When the hammer is down, as shown in Fig. 1,the connection E is in such position that the pressure of the spring isdi:

rectly upon the hammer for retaining it upon the base of the cam. As thehammer rises the link is moved from its right-angled position withreference to the arm of the hammer, and the angle is gradually increaseduntil, when the hammer reaches its highest point, as. in Fig. 2, thelink is nearly in line with the handle of the hammer, and the pressureof the 2. In stop-watches, the combination of the cam B, the pivotedhammer D, spring 0, and flexible connection E, substantially asdescribed, for operation'as specified.

The above specification of my invention signed by me this 11th day ofSeptember, 1882.

AMI LE OOULTR'E.

WVitnesses:

LYELL T. ADAMS, F. FAUQUE.

